Thioethers and thioketones of thiazolone cyanine dyes as dyestuff intermediates



Patented Jan. 2, 1951 UNITED STATE THIOETHERS AND THIOKETONES OF THI- AZOLONE CYANINE DYES AS DYESTUFF INTERMEDIATES Thomas R. Thompson, signor toNGeneraI An Binghamton, N. Y., asiline & Film Corporation,

New York, N. Y., a corporation of Delaware No Drawing. Application December 21, 1948, 1 Serial No. 66,572

4 Claims. (Cl. 260-2401) This invention relates to cyanine dyestuff intermediates and particularly to thioethers of alkylidene thiazolone cyanines and inner salts of thioalkylidene thiazolone cyanine dyes as intermediates for the preparation of chain-substituted triand tetranuclear cyanine dyes for sensitizing silver-halide emulsions.

It is known that in the preperation of chain, substituted trinuclear dyes, it first is necessary to condense a quaternary saltof a heterocyclic nitrogen compound having a reactive methyl group, in the presence of an anhydride of a monobasic acid and an acid binding agent, with a 5-membered, 3-alkyl, 3-aryl, or 3-aralkyl substituted derivative of rhodanine, such as, for example, 3- methylrhodanine. The resulting thioketone is then reacted with an alkyl salt, for example, methyl-p-toluene-sulfonate, to give a methylmercapto derivative. This derivative is then condensed with a cyclammonium quaternary dye salt having a reactive methyl group in the 2-po-- sition of the nitrogen atom thereof to give a chain-substituted trinuclear dye. The procedure involved entails 3 separate reactions and is time consuming. i I have found that thiazolone cyanine dyes can be readily converted to thioethers, as hereinafter described, which readily react with heterocyclic quaternary salts containing a reactive methyl group, in one condensation reaction, to yield chain-substituted trinuclear dyes. When such thioethers are treated with heterocyclic keto methylene compounds, such as rhodanines, novel chain-substituted trinuclear dyes result. When treated with thiazolone cyanine dyes, both symmetrical and unsymmetrical chain-substituted tetranuclear dyes are obtained. Although symmetrical chain-substituted tetranuclear dyes are known, there is no method, other than by the use of the intermediates of the present invention, which would lead to unsymmetrical tetranuclear dyes.

The thiazolone cyanine dye intermediates prepared according to the present invention are characterized by the following general formut=ca o v N \N. J wherein n p ents a a y ererj el y j oi pi e. g., methyl, ethyl, propyl, isopropyl,

benzyl, ,9-

phenethyl, and the like, R1 represents an alkyl group, e. g., methyl, ethyl, propyl, isopropyl, butyl,

isobutyl, etc., R2 represents an alkyl, alkenyl, aryl, or aralkyl group, e. g., methyl, ethyl, propyl, allyl, phenyl, naphthyl, tolyl, benzyl, p-henethyl, and

i the like, R3 represents an aliphatic radical, e. g.,

methyl, ethyl, propyl, butyl, hydroxethyl, ethoxyethyl; an aryl or aralkyl radical or substituted groups of this type, e. g., phenyl, naphthyl, tolyl, benzyl, menaphthyl, and the-like, X represents an acid radical, e. g., chloride, bromide, iodide, or alkyl sulfate, alkyl p-toluenesulfonate or perchlorate, and Z represents the atoms necessary to complete a nitrogenous heterocyclic ring system. of the type used in cyanine dyes such as pyridine, pyrroline, lepidine, quinoline, indolenine, oxazole, thiazolone, thiazole, thiodiazole, selenazole, selenazoline, oxazoline, benzothiazole, benzoselenazole, benzoxazole, naphthothiazole, peri-naphthothiazole, naphthoselenazole, and the like.

The dyestufi intermediates characterized by the foregoing formulae are obtained by treating a thiazolone cyanine dye with an aliphatic acid anhydride in the presence of a mixture ofpyridine and triethylamine followed by treatment with phosphorus pentasulfide to yield the thio derivative which is subsequently alkylated with an alkylating agent in the usual way to yield the thioether derivative. The thiazolone cyanine dyes utilized in this reaction are characterized by the following general formula:

. butyric, isobutyric, n-valeric, and isovaleric anhydrides.

As alklating agents which may be employed in alkylating the thio derivative, the following may be mentioned: alkyl esters, such as methyl sulfate, or methyl, ethyl, propyl, or isopropyl derivatives of p-toluenesulfonates, and aralkyl halides, such as benzyl chloride, s-phenethyl bromide and the like.

I The following examples describe the preparaaliphatic anhydrides, the fol; propionic, N'-' tion of some of the thiazolone cyanine dyes which are utilized in the preparation of the dyestuff intermediates:

Example I Example II 6.9 grams of a-(1-ethyl-3,3,5-trimethylindolinylidine)-thioacetanilide were heated with 6.9

grams of bromoacetic acid in cc. of n-butanol at 105-110 C. for 10 minutes. The mixture was treated with ether and the ether layer decanted. The black liquid was stirred with isopropanol and filtered. The residue was recrystallized from methanol to yield 1.7 grams of the final dye havinga melting point at 236-238 C.

Exa III meltin at 83 8 A mixture of a-(3,5-dimethyl-4=phenylthiazolylidine) -thioacetanilide, 1.0 gram of brcmoacetic acid, and 2 cc. of acetic acid was heated at C. for 1 hour. The product was precipitated with ether and subsequently washed with ether by decantation. The viscous product does not solidify and may be used directly in dye synthesis.

Example V A mixture of 5.5 grams of a-(I-methyI-Z-quinolylidine) -thioacetanilide and an equal weight of bromoacetic acid was dissolved in 50 cc. of nebutanol and heated at 100 C. fo 10 minutes. 011

. cooling, yellow crystals formed which were filtered and washed with ether. Recrystallization from methanol yielded yellow crystals melting at 212 0.

Example VI C2115 Br Amixture of 1.5 grams of a-(3-vethylbenzothiazolylidine) -4-ethylthioacetamide, 1.5 grams of bromoacetic acid and 5 cc. of acetic acid was heated at C. for 5 minutes. After cooling, the product was precipitated with ether and dried to yield 2.07 grams.

The amines of the foregoing thiazolone cyanine dye salts may be replaced by iodide, thiocyanate, or perchlorate ions by treating an alcohol solution of the dye saltwith an aqueous or alcoholic solution containing a sodium or potassium salt of the desired anion.

The following examples describe the preparation of the thiazolone cyanine dye intermediates from the foregoing thiazolone cyanine dyes. It is to be understood that they are given merely for the purpose of illustration and are not to be construed as limitative.

Exa ple. VI 0 2H5 A mixture of 75 cc. oi pyridine, 10 cc, of propionic anhydride, 10 cc. of triethylamine, and 13.0

grams of the thiazolone cyanine dye of Example I was heated with stirring at 120 C. for 20 minutes. During the course of 10 minutes, a total of 10 grams of phosphorus pentasulfide was added in portions at 120 C. After an additional 10 minutes heating and stirring at 120 (2., the mixture was poured into cold water and stirred until the first formed oil solidified. The crude product was stirred with 300 cc. of a 10% aqueous solution of sodium hydroxide and purified by boiling 9 .11% with isopropanol- Th re, a b ai d 2 ano es? grams of yellow powder which decomposes at about 200 C.

A mixture of 9.3 grams of the yellow powder and grams of methyl D-toluenesulfonate was fused at 95 C. for one hour. After cooling, the product was washed with ether and dissolved in 10 cc. of warm acetone. The final product was precipitated as the iodide by adding 25 cc. of methanol containing 20% sodium iodide. The product was washed with water and purified by boiling out with isopropanol. A yield of 4.3 grams of a product melting at 225-228 C. was obtained.

Example VIII CHaSO A mixture of cc. of pyridine, 2 cc. of propionic vanhydride, 2 cc. of triethylamine, and 2.0 grams of the thiazolone cyanine dye of Example II was heated at 120 C. for 3 minutes. There were then added 2.0 grams of phosphorus pentasulfide and the mixture heated at 115 C. for 15 minutes. A dark red oil was precipitated by the addition of 100 cc. of water and washed with water by decantation. The product was fused with 3 cc. of methyl sulfate at 95 C. for 10 minutes to yield 4.5 grams of a yellow-orange solution which may be employed in dye syntheses.

Example 11: v

N OCH:

Example X.

To a mixture of '75 cc. of pyridine, 15 cc. of propionlc anhydride and 15 cc. of triethylamine was added the washed heavy oil ofjExample IV and the resulting solution heated at 120 C. for 30 minutes. Fifteen grams of phosphorus pentasulflde were added in portions and the reaction mixture stirred at 120 C. for 30 minutes. The product was isolated by pouring the reaction mixture into 300 cc; of water. The product was purified by washing with water and subsequently grinding with acetone. A yield of 10.9 grams of yellow glistening crystals melting at 255-260 C. was obtained.

A mixture of 25 grams of the compound of Example I, 20 cc. of n-butyric anhydride, cc. of pyridine and 20 cc. of triethylamine was heated and stirred at 120 C. for 20 minutes. There was then added 20 grams phosphorus pentasulfide and stirring at 120 C. continued for 20 minutes. The reaction mixture was poured into 700 cc. of cold water. Th resulting brown precipitate was filtered off, washed with water, and boiled out with 100 cc. of isopropyl alcohol. A yield of 20.9 grams of the dried and purified product was obtained. The compound is presumed to be an inner salt characterized by the following formula:

' A mixture of 2.0 grams of the above material and 2.0 grams of ethyl p-toluenesulfonate was Example XII apnea. C (E 4} A mixture of 4 cc. of benzyl bromide and 2.0 grams of the inner salt prepared according to Example XI was fused at C. for 30 minutes. The reaction product was washed with ether to A mixture of 25 grams of the compound of Example I, 20 cc. of isovaleryl chloride, 100 cc. of pyridine, and 20 cc. of triethylamine was heated and stirred at 120 C. for 30 minutes. There wasthen added 20 grams of phosphorus pentasulfide and the stirring at 120 C. continued for an additional twenty minutes. The reaction mix ture was poured into 580 cc. of water and the precipitated viscous semi-solid washed with water by decantation. After boiling-out with 180 cc. of isopropyl alcohol, the material solidified. A yield of 17.1 grams of a brown powder, melting at. 203209 C. was obtained. This material was. fused with methyl sulfate to give the reactive dye intermediate illustrated by the above formula.

The thio derivative obtained according to Examples IX and X may also be converted into their corresponding alkyl and aralkyl thioethers by fusion of the thio derivative with an alkyl or aralkyl halide, or by heating the thio derivative with an alkyl or aralkyl salt such as the sulfate, p-toluenesulfonate or halide, i. e., chloride or bromide in a sealed tube in a water bath under increased pressure. I

While I have disclosed the preferred embodiments of my invention and the preferred modes of carrying the same into effect, it will be readily apparent by those skilled in the art that many variations may be made therein Without departing. from the spirit thereof. Accordingly, the scope of my invention is to be limited solely by the appended claims.

I claim:

1. A thiazolone cyanine dyestufi intermediate characterized by a formula selected from the class consisting of the following formulae:

"use

it: Baa wherein R. represents a member selected from thEfClfiSS consisting of alkyl andaralkyl groups, R1 represents an alkyl group, .32; represents a member selected from the class consisting of alkyl, allyl, aryl, and aralkyl' groups, R'z'r'epre'sents a member selected-from the class consisting of lower alkyl, lower hydroxyalkyl, lower alkoxyalkyl, aryl of the benzene and naphthalene series, and aralkyl groups, X represents an acid radical, and Z represents the atomsnecessary to complete a heterocyclic nitrogenous nucleus of the type used in cyanine dyes.

2. A thiazolone-cyanine dyestu-if intermediate of the formula:

A thiazolone cyanine dyestuff intermediate he formula:

- I Se OCH:

THOMAS R. THOMPSON.

No references cited. 

1. A THIAZOLONE CYANINE DYESTUFF INTERMEDIATE CHARACTERIZED BY A FORMULA SELECTED FROM THE CLASS CONSISTING OF THE FOLLOWING FORMULAE: 